Geate foe steam boilees



(No Model.) 2 Sheets-Sheet 1. A DAVY 8: J EDEY GRATE FOR STEAM BOILERS.

N0. 606.19 Patented June 28,1898.

WZZW/eJJw I (No Model.) 2 Sheets-Sheet 2. A DAVY & J EDBY GRATB FOR STEAM BOILERS.

No. 606,191. Patented June 28,1898.

lllll llllll IlllIH Ill PATENT FFIGEQ ALFRED DAVY AND JOHN EDEY, OF LONDON, ENGLAND.

GRA l'E FOR STEAM-BOILERS.

SPECIFICATION forming part of Letters Patent No. 606,191, dated June 28, 1898. Application filed July 21, 1897. Serial No. 645,455. (No model.) Patented in England .Tune 4, 1897,No.13,774.

To all whom, it may concern.-

Be it known that we, ALFRED DAVY, engi neer, 0f 4 \Voburn Place, London, W. 0., and JOHN EDEY, colliery proprietor, of 16 Eastcheap, London, E. (3.. England, subjects of the Queen of Great Britain, have invented certain new and useful Improvements in Grates for Steam-Boilers, (for which we have obtained Letters Patent in Great Britain, No. 13,774, dated June 4, 1897,) of which the following is a specification.

Our invention has for its object improvements in grates for steam-boilers, which are so constructed that the parts exposed to the action of the fire when at a high temperature are able to sustain the heat and rapid circulation of the water is obtained, at the same time resulting in considerable economy of fuel and greater boilerefficiency, with also the possibility of using fuel of an inferior kind.

In order that our invention may be clearly understood and moreeasily carried into practical effect, we have appended hereunto drawings showing one of our grates applied to an ordinary double-flue boiler, which will make its applicability to other boilers quite simple, and it will be clearly understood that the same may be applied to a furnace or fire external to any steam-boiler and where the waste heat or a portion of the heat from such furnace is used for other purposes than entirely for the generation of steam.

Figure 1 is the front elevation of a doubleflue boiler with fire-doors and other wellknown boiler-fittings not applied or removed therefrom, but showing the most necessary parts of the arrangements of our grate applied thereto. Fig. 2 is a vertical side elevational section through one of the fiu-es F, with the boiler broken off behind the bridge A as regards its length. Fig. 3 is a horizontal sectional plan through the lines F F. Fig. 4 is a cross-sectional elevation through the boiler and fireplace behind the dead-plate D, showing one kind of Water-bridge in the right-hand flue and another kind of water-bridge in the left-hand flue. Fig. 5 shows a broken-off section through one kind of bridge.

In the sides of the lines F we fix water-plugs S, communicating with the water inside the boiler, or instead of two separate plugs we may run a water-tube entirely across the flue under the dead-plate D and upon which the dead-plate rests and is quite free to move outwardly or inwardly as the tubular grate-bars T increase or decrease in length, due to expansion and contraction in their length. This dead-plate may be a hollow casting of steel or it may be built up in plates; but in an ycase the front ends of the tubes T are connected with the insides of the dead-plate D and bridge A by water-tight junctions, and the dead-plate is free to slide upon the waterstuds S or their equivalent cross-tube before mentioned. The water bridge A may be made in one part or built up with the flue F, as shown in elevation in the left-hand flue, Fig. 4, or it may consist of a hollow separate piece, as shown in front elevation in the righthand flue, Fig. 4, and in side elevation at Fig. 5, in which case a branch a (shown partly in section) communicates with the boiler through the passage a being hung or suspended from the flue F by the flange a but in any case the water-has free access to the inside of the water-bridge, and thence to the hollow tubular bars T, through which it freely circulates to the dead-plates D.

It will be evident that the bridge A may be made in a number of designs and shapes to suit the purpose; but when applied to boilers already at work we prefer to fill in the spaces a a with fire-bricks or blocks of fire-clay and when necessary to build the front of the bridge up between the part a of the bridge and the top of the flueF to prevent the flames or heat passing the bridge at the upper portion of the flue; but when the bridge is built :up as a portion of the boiler-flue F, as shown fire-grate from the bridge to the dead-plate A. Two or more of these tubes are preferably used as longitudinal stays between the bridge A and the dead-plate D to withstand the pressure endwise between the two. At the front of the hollow dead-plates D branch pipes 12 and o communicate with the interior of the dead-plates and then through the pipes 41 and 1:, through the valves V and V, with the interior of the boiler or other steamchambcr, so that a constant circulation is set up and maintained from the boiler through the branches a of the bridges A and along the tubular bars T and dead-plates D and pipes t and o and valves or cocks V and V into the front end of the boiler. The central valve-box V is set below the line of the pipes o and 22 so that when the valve of the valvebox is closed the communication is quite clear above it, but when the valves V and V are closed and V is open the deadplates D, tubular bars T, and bridge A are thoroughly blown through and cleansed, the accumulation deposit, if any, being carried down the pipe 10 into the drain. It must be understood thatthe dead-plates D are always free to move with the expansion of the tubular bars T, and for this purpose the pipes o and may be made of copper or have bends or flexible joints or junctions in connection therewith to allow of such freedom of movement with suflicientstability coupled with sufficient flexibility of the parts. \Ve have said that the dead-plates slide upon the round studs S or equivalent tubes, but friction ferrules or rollers may be mounted upon such studs or tubes to facilitate such movement with freedom. The tubular bars,if long,may be supported across the center or other part of their length by a cross water-tube S or more than one such support.

The operation of the furnace is as follows: hen the fire is made, the deflector-plate K, which may be hinged or removable or fast,defleets the inlet-air upon the surface-fuel, and all the smoke and gases are carried by the draft downward through the fire, as they cannot pass the bridge on a level with or above the iire in the direction of the arrows and then turn upward as they pass onward along the fines. The bottoms of the flues F are thus utilized as heating-surface and a most intense heat is maintained in the fire-boxes and the fines without making any smoke even when inferior fuel is being used.

The dead-plate D,in the case of a flue-boiler,

should be made as thin in depth as practicable, and the pipes 41 and 17 are so arranged in regard to their area as to be equal or about equal to the combined sum area of all the tubular bars T. It is also necessary to so arrange the sizes and thicknesses of these parts that doors fitted above the dead-plate and below the dead-plate, so as to close up the front of the lines, may be easily operated without impediment to their free action. lVe generally find that cocks are more compact for the front pipes than valves. Expansion and contraction may be provided for at the bridge by making the connection or pipe a of copper or of such a shape as to allow of a limited movement.

lVhat we claim, then, is-

In combination, the sliding hollow deadplate D, the water-bridge A engaging the inner wall of the boiler, the hollow grate-bars connecting the dead-plate and the waterbridge, the outside tubes '0 o connccted with the water-space of the boiler and with the dead-plate and an outlet-tube \V, said tubes having valves whereby when the tube \V is closed and the tubes 2; o are open the water under pressure of the boiler will pass through the grate-tubes and the water-bridge,substantially as described.

In testimony that we claim the foregoing as our own we afiix our names in the presence of two witnesses.

ALFRED DAVY. JOIIN EDEY. Vitnesses Farm. 0. ARIES, WALTER .T. SKER'IEA. 

